Tell the root layer it has a wheel handler when a select is active

Source/web/WebViewImpl.cpp

 /*
  * Copyright (C) 2011, 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 1513 matching lines @@
         currentFrame = currentFrame->tree()->parent();
     }
     return scrollHandled;
 }
 
 void  WebViewImpl::popupOpened(WebCore::PopupContainer* popupContainer)
 {
     if (popupContainer->popupType() == WebCore::PopupContainer::Select) {
         ASSERT(!m_selectPopup);
         m_selectPopup = popupContainer;
+        m_rootLayer->setHaveWheelEventHandlers(true);
     }
 }
 
 void  WebViewImpl::popupClosed(WebCore::PopupContainer* popupContainer)
 {
     if (popupContainer->popupType() == WebCore::PopupContainer::Select) {
         ASSERT(m_selectPopup);
         m_selectPopup = 0;
+        m_rootLayer->setHaveWheelEventHandlers(false);

[jamesr, 2013/09/20 18:04:10]

what if the root layer actually had wheel event handlers before the popup
opened?  i think you need to save the bit off in popupOpened()

     }
 }
 
 PagePopup* WebViewImpl::openPagePopup(PagePopupClient* client, const IntRect& originBoundsInRootView)
 {
     ASSERT(client);
     if (hasOpenedPopup())
         hidePopups();
     ASSERT(!m_pagePopup);
 
@@ skipping 2619 matching lines @@
     //    the initial viewport width.
     // 2. The author has disabled viewport zoom.
 
     const PageScaleConstraints& constraints = m_pageScaleConstraintsSet.pageDefinedConstraints();
 
     return fixedLayoutSize().width == m_size.width
         || (constraints.minimumScale == constraints.maximumScale && constraints.minimumScale != -1);
 }
 
 } // namespace WebKit